lockd: lockd server-side shouldn't set fl_ops

[ Upstream commit 7de875b231edb807387a81cde288aa9e1015ef9e ]

Locks have two sets of op arrays, fl_lmops for the lock manager (lockd
or nfsd), fl_ops for the filesystem.  The server-side lockd code has
been setting its own fl_ops, which leads to confusion (and crashes) in
the reexport case, where the filesystem expects to be the only one
setting fl_ops.

And there's no reason for it that I can see-the lm_get/put_owner ops do
the same job.

Reported-by: Daire Byrne <daire@dneg.com>
Tested-by: Daire Byrne <daire@dneg.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>